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construct/include/ircd/db/delta.h
2018-02-07 23:15:17 -08:00

71 lines
2.1 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_DB_DELTA_H
namespace ircd::db
{
struct delta;
enum op :uint8_t;
// Indicates an op uses both a key and value for its operation. Some only use
// a key name so an empty value argument in a delta is okay when false.
bool value_required(const op &);
string_view reflect(const op &);
}
/// Types of delta operations
enum ircd::db::op
:uint8_t
{
GET, // no-op sentinel, do not use (debug asserts)
SET, // (batch.Put)
MERGE, // (batch.Merge)
DELETE, // (batch.Delete)
DELETE_RANGE, // (batch.DeleteRange)
SINGLE_DELETE, // (batch.SingleDelete)
};
/// Update a database cell without `cell`, `column` or row `references`.
///
/// The cell is found by name string. This is the least efficient of the deltas
/// for many updates to the same column or cell when a reference to those can
/// be pre-resolved. This delta has to resolve those references every single
/// time it's iterated over; but that's okay for some transactions.
///
struct ircd::db::delta
:std::tuple<op, string_view, string_view, string_view>
{
enum // for use with std::get<VAL>(delta)
{
OP, COL, KEY, VAL,
};
delta(const enum op &op,
const string_view &col,
const string_view &key,
const string_view &val = {})
:std::tuple<enum op, string_view, string_view, string_view>
{
op, col, key, val
}{}
delta(const string_view &col,
const string_view &key,
const string_view &val = {},
const enum op &op = op::SET)
:std::tuple<enum op, string_view, string_view, string_view>
{
op, col, key, val
}{}
delta() = default;
};